Overview of CanSat Imaging System

1
Overview of CanSat Imaging System
2
Personnel

• EE Members
• Nigel Dunham Senior EE, CanSat Team Leader.
• YiYang Senior EE.
• Ibrahima Diack Senior EE.
• Anthony Olson Senior EE.
• Mishari Al-Nahedh Senior EE.
• AE Members
• Stephen Mance Sophomore AE, AE team leader.
• Laura Stiles Sophomore AE.
• Jess Snyder Sophomore AE.
• Ryan Shaffer Sophomore AE.
• Dr. Prescott and Dr. Sorensen are also the
  CanSat competition advisors

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Outline of Approach

• The CanSat system must
• Capture multiple ground images
• Assemble ground images to create a map of the
  ground using commercial or custom software.
• Imaging system needs to compensate for rocking,
  etc. while aerial.
• Record the time, position, and altitude when each
  digital image was taken.
• Display position, altitude, orientation, and the
  time the image is captured in real time at the
  ground command center using capable software.
• A command uplink starts recording of digital
  images.

4
Design Constraints

• All structure and components shall fit inside
  soda can
• The CanSats total mass will be 370 grams or less
• A parachute will be sized for a flight of at
  least three minutes and less than seven minutes
• The parachute must survive 20 Gs of shock
• Flexible wire antennas are allowed to extend
  beyond the surface of the CanSat opposite of the
  parachute.
• The CanSat power must last at least one hour.
• The CanSat operation must be activated by an
  activation uplink command.
• Operations cannot start until the uplink command
  is received.
• The activation uplink command may be sent after
  the launch control officer (LCO) allows the
  operation.
• The cost of the CanSat hardware must not exceed
  500.

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Block Diagram of CanSat System

• 4 Subsystems
• Imaging
• Communications
• Navigation
• Structure

Important Note U-processor encompasses the
entire project and all 5 team members will work
on this aspect for each subsystem.
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Microcontroller

• CanSat will require microcontroller to have
• RS232 for digital GPS data
• Minimum of 6 I/O channels
• 3 for GPS data
• 1 for Imaging
• 1 for Tx and 1 for Rx

• Possible Microcontroller
• Model Parallax BASIC Stamp DC-16
• Very good in terms of cost vs. functionality
• (30 for complete u-processor with 16 I/O
  channels)
• High ratings for simplicity of programming

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Structure and Parachute

• Structure
• The structure that will house the avionics will
  be built by the AE team. This structure will fit
  inside a 12 oz soda can.
• It will be custom made of a lightweight
  carbon-fiber composite

• Parachute Design
• Parachute will be designed by AE team
• Design is in accordance with design
  constraints
• Material will be light weight, strong and
  flexible

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Imaging Subsystem
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Image Capturing

• The CanSat system will capture multiple ground
  images and then assemble these images to create a
  map of the ground using commercial or custom
  software.

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Available Devices (1)

• Place a digital camera in side the CanSat system
• Send a periodic signal to the shutter to take
  pictures
• Retrieve images saved in the cameras memory
  using a UBS cable connect to the computer.

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Available Devices (2)

• Place a mini video camera inside of the CanSat
  system
• Transmit real-time video signal back to control
  center
• Capture images at the control center

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Comparison

• Using a digital camera to take aerial pictures is
• a better choice because
• Easy to rectify.
• No need to provide power to the transmitter.
• Easy to retrieve images.

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Imaging Design Constraints

• Weight
• Size
• Cost
• Image quality
• System Stability

14
Possible Design

• Adequate room for the imaging system
• Stability

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HF Radio Transceivers
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Transceivers

• What is the Need?
• Reliably exchange data between
• CanSat and ground station
• Wireless Transceiver
• IEEE 802.11
• Optical transceivers
• RF Transceivers

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Choosing a Transceiver

• Range (over Two miles)
• - 802.11 offers ranges up to 100 meters
• - Infrared technology only several feet
• - RF communications up to several mile
• Interferences
• - 802.11 uses Direct Sequence Spread Spectrum
  for max throughput
• limited ability to overcome fading and in
  band jammers
• - Interferences not an issue for optical
  communications
• - RF transceivers use Frequency Hopping Spread
  Spectrum to avoid
• interferences

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Choosing a Transceiver

• Long Range Requirements
• Output power
• More output power will boost signal. (1W?30dB
  vs. 100mW ?20dB link budget)
• Downside is that applications need to be
  compact and power efficient
• Receiver Sensitivity
• Every -6dB doubles range in line of sight
  conditions (or -10dB indoor)
• Industry average is -93 dBm
• Antenna Gain
• Higher gain results in a greater range
• Line of Sight
• Range diminishes indoor

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Buying VS Building

• 900-928 MHz RF transceivers for this project
• Cost to build is about 20
• However cost doesnt include testers, software
  and regulatory very time consuming
• Modules can be bought for about 60
• Consider building when thousands of transceivers
  are involved

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Potential Modules

• Honeywell HRF-09325XM
• Up To 6 dBm Output Power Into 50 Ohms
• 20mA Transmit Current At 1mW Output, 33mA Receive
  Current
• Direct Connection To Microprocessor Via SPI Bus
• Integrated Ant. Switch
• Receiver Has 85 dbm Sensitivity at 19.2 kbps
• Digital Encoding, Decoding
• 23mm x 23mm x 4.5mm , Surface Mountable
• Prog. Power Levels, Freq. And Tx/Rx/Standby
• Operates From Single 2.8-3.3v Power Supply

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Potential Modules

• Aerocomm AC 4790 RF
• True peer-to-peer protocol.
• Ultra-fast sync time (25 msec).
• Small form factor 1.65 x 1.9 inches.
• API commands to control packet routing.
• Software-controlled sensitivity.
• Network node discovery.
• Offers Ranges up to 4 miles
• Variable output power 5mW to 1000mW
• Operates from single 3.3V to 5.5V
• power supply
• Typical power consumption 68mA

AC 4790 Module
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Interface With Microcontroller
Same serial data rate required for communication
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GPS Navigation Subsystem
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Position and Altitude

• What is needed
• Position (longitude and latitude)
• Altitude
• Time
• What are the different options?
• Pressure sensor
• altitude
• Global Positioning System GPS
• Position, altitude, and time

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Pressure Sensor background

• The pressure sensor measures the atmospheric
  pressure and generates a voltage proportional to
  the air pressure.
• The higher the air pressure, the higher the
  voltage.
• Example manufacturer equation
• V 5.0(0.009P 0.095) P 22.222 V 10.556
• This should result in a number between 100 and
  102 kPa at sea level
• At an altitude of 3000 ft. above sea level gt 70
  kPa

Pressure Sensor
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GPS background

• Global Positioning System (GPS) is a
  satellite-based navigation system
• 24 satellites are in orbit around earth at an
  altitude of 12,000 miles or 20,000 km
• Satellite velocity 7,000 mph
• Each satellite orbits the earth twice daily
• Advantages to GPS
• GPS works in any weather conditions, anywhere in
  the world, 24 hours a day.
• There are no subscription fees or setup charges
  to use GPS.

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GPS Background

• Three satellites are needed to calculate 2D
  position (longitude and latitude)
• Four satellites are needed to calculate 3D
  position (longitude, latitude, and altitude)
• Accuracy is 15 - 20 feet for newer models
• Signals transmitted
• 8 low power signals
• L1, L2, L3, , L8
• Civilian use L1 at 1575.42 MHz

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GPS Background

• GPS Receiver
• Axiom Sandpiper II GPS Module
• Channels 12
• Frequency L1 1575 MHz
• Altitude -3000 ft to 30,000 ft.
• Accuracy lt15m or 49 ft.
• Serial Interface RS-232
• Size 1.6 x 2.8 x 0.35 in.
• Weight 20 grams
• Cost 25 - 30
• Antenna
• Any GPS antenna with SMA connector
• Cost 15 - 20

Axiom Sandpiper II GPS Module
Trimble Mini GPS Antenna with SMA connector
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Interface with Microcontroller
Transmission to ground unit must be done in Real
Time.
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Project Strategy
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Division of Labor

• The CanSat system will be divided into 4
  subsystems Imaging, Data Transmission,
  Navigation, and Structure.
• The overall team will break off into technology
  groups and design/debug each subsystem
• Imaging Team Yi Yang and Anthony Olson
• Data Transmission Team Nigel Dunham, Mishari
  Al-Nahedh, Ibra Diack
• Navigation Nigel, Yi, Anthony, Mishari, Ibra
• Structure Team AE team members
• After the completion of each subsystem, the
  entire team will configure our selected
  microcontroller to work with every specific
  subsystem.

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Plan of Action

• The following must be accomplished in an
  extremely timely manner
• Select digital camera for imaging portion of
  project. (completed)
• Design, build, and test imaging portion of
  CanSat.
• Design, build, and test two transceivers that
  will be used for wireless communication between
  the CanSat and the ground command center
  (laptop).
• Select and modify GPS unit that will provide
  position, altitude, and time stamp of the digital
  images.
• Configure microcontroller for interfacing with
  the imaging system, navigation system, and the
  wireless communication system.
• Write program(s) that will control the functions
  inside of the microcontroller.
• Programs and tasks that cannot yet be estimated.
• Test the completed CanSat system using HABS.

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HABS

• High Altitude Balloon System (HABS)
• HABS can lift 18.5 pounds.
• HABS with CanSat will be allowed to rise to an
  altitude of 7500-9000 feet above the ground
  surface. This should allow for reasonable
  testing of all subsystems.
• Testing will take place at the KU soccer practice
  field located at 23rd and Iowa (shown below).

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Project Milestones
Milestone 1 Imaging and TxRx subsystems should
be complete and microprocessor should be
configured for reliable operation.
Milestone 2 All subsystems should be completed
and HABS testing should begin immediately.
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Weekly Schedule of Tasks
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Risks and Contingency Plan

• Main areas of risk and possible solution
• Problem Weight limit of 370 grams
• Solution Careful design of system paying
  serious detail to weight of components
• Problem Many components are highly sensitive to
  electrostatic discharge
• Solution Anti-static mats or bands should be
  used
• Problem Ceiling of 500 for hardware
• Solution Building as much of the system as
  possible will help with the overall cost limit
• Problem Unfamiliar technology will be used
• Solution A team effort will be used to learn
  new software, etc.

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Contingency Plan

• We have allowed enough time for completion of
  each subsystem, in case of subsystem failure. If
  subsystem failure occurs
• Re-examine system design
• Double check programs and timing of
  u-controller
• Re-test system
• Get outside help (Dr. Prescott, Dr. Sorensen)
• If problem isnt fixed, we must redesign
  subsystem

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Questions?